Question

Using Archimedes' principle, describe an experiment to find the relative density of a solid which floats on water.

Answer 1

We can find the relative density of a solid which floats on water by following the experiment.

Measuring the relative density of a cork

Choose a sinker and find its weight in water by suspending it in water.

Tie the solid to the string attached to the sinker and find its weight in air but sinker in water.

Remove the solid and tie it together with the sinker and suspend it in water and find the weight of the solid together with the sinker in water.

Record your observation as shown below:

Weight of sinker in water = x gf

Weight of sinker in water + solid in air = y gf

Weight of solid in air = (y - x) gf

Weight of solid + sinker in water = z gf

upthrust on solid in water = (y - z) gf.

The upthrust on in water also represents the weight of the water displaced by the solid. Relative density of solid = (weight of cork in air )/(weight of equal volume of water) Relative density = (y - x)/(y - z).